SPECTROSCOPIC AND CONDUCTOMETRIC STUDIES OF LANTHANIDE SOAPS

Infrared spectral studies of lanthanide soaps (octanoates of cerium, didymium, neodymium, and samarium) reveal that fatty acids exist with a dimeric-type structure through hydrogen bonding between two molecules of fatty acids, whereas the metal-to-oxygen bonds in these soaps have an ionic character. The X-ray diffraction results confirm that these soaps have a double-layer structure with molecular axes slightly inclined to the basal plane. The premicellar association and the formation of micelles in lanthanide soap solutions have been investigated by conductometric measurements in a nonaqueous medium. The molar conductance at infinite dilution, the degree of ionization and the ionization constant have been evaluated. The results show that these soaps behave as weak electrolytes in dilute solutions.